1. Field of the Invention
The present invention relates to a cement resistor having a bent resistive element of metal which is placed in a box-shaped ceramic case with an open side and sealed by a cement material that is introduced through the open side to fill the ceramic case.
2. Description of the Related Art
Cement resistors are known in the art as small-size, high-power-capacity current-detecting resistors. For example, reference should be made to Japanese laid-open patent publication No. 11-251103. One cement resistor has a resistive element in the form of a bent plate of copper-nickel alloy which is placed in a box-shaped ceramic case and sealed by a cement material that fills the ceramic case. The cement resistor is fire-resistant, has a low resistance value of several tens mΩ or lower which is easy to obtain, and has a good temperature coefficient of resistance (TCR). Therefore, the cement resistor is widely used in the art as a small-size, high-power-capacity current-detecting resistor.
The heat dissipation of resistors is of great importance to small-size, high-power-capacity resistors. Various proposals have been made to improve the heat dissipation of resistors. For example, reference should be made to Japanese patent No. 3358844.
Demands are growing in the art for cement resistors which are of higher power capabilities, smaller sizes, higher performance, and greater reliability.